Non-linear hysteresis modelling of piezoelectric actuator using feedforward with PI control for micromanipulation

The hysteresis characteristics of piezoelectric actuators has a major deficiency in a wide variety of micro position controls. Due to the hysteresis, positioning errors occur predominantly on the PEA-based microsystems. This work involves an identification of appropriate hysteresis model and control system for precisely actuating the PEA in the micrometre to sub-nanometer displacements. The hysteresis characteristics of PEA are modelled using Bouc–Wen (BW) and Dahl hysteresis model among the several hysteresis compensators. The control strategies such as PID and Feedforward PI controller were experimented to improve the positional accuracy of the single-axis piezoelectric actuation to achieve the 100 µm positional task. From the results, it has been inferred that the Dahl hysteresis compensator with Feedforward PI controller gives a positional accuracy of 99.752 µm which is better than the BW hysteresis compensator positional accuracy of 99.567 µm. The Dahl hysteresis compensator with Feedforward PI controller gives minimum RMS, ISE and IAE values of 0.192 µm, 0.167 µm and 0.146 µm respectively while compared to the BW hysteresis with feedforward PI controller gives the RMS, ISE and IAE values of 0.198 µm, 0.179 µm and 0.157 µm respectively. The nonlinear Dahl hysteresis compensator with Feedforward PI controller gives the better results than other methods investigated in this work.